Graph broken with cyclic dependencies

[himanshisrivastava]

I have a graph with cycle on the root node as shown below:
1 --> 2 --> 3 --> 1
Now when I try to print the order of graph (graph.overallOrder()), this returns empty.

But it works fine with below scenario
0 -->1 --> 2 --> 3 --> 1

Here is the code:

const GRAPH = require('dependency-graph').DepGraph;

// Working
let a = new GRAPH({ circular: true });

a.addNode(0);
a.addNode(1);
a.addNode(2);
a.addNode(3);
a.addDependency(0,1);
a.addDependency(1,2);
a.addDependency(2,3);
a.addDependency(3,1);

console.log(a.overallOrder()); // returns correct order

/*
**************************
*/

// Not working
let a = new GRAPH({ circular: true });

a.addNode(1);
a.addNode(2);
a.addNode(3);
a.addDependency(1,2);
a.addDependency(2,3);
a.addDependency(3,1);

console.log(a.overallOrder()); // returns empty array

[jriecken]

I'll take a look when I get a bit of time - I think it's because there are no clear starting points (nodes with nothing depending on them) to run the DFS from.

Currently the circular option just suppresses the error that happens when a cycle is detected. A true topological ordering (what overallOrder does) is really only possible when the graph is acyclic.

That being said - I can probably make it return some ordering in this case when circular is true) rather than an empty array.

[jriecken]

Should be fixed in version 0.8.1.